A 10 a.m. test tornado warning will be issued for all Illinois counties, according to the NWS. Many locations will also test outdoor warning sirens. TV and radio affiliates will interrupt broadcasts with the drill and weather alerts will activate in the same way as they would if there were a real tornado traveling through the state.

The test will be disseminated through the National Oceanic and Atmospheric Administration’s weather radio with the same tone alarm and codes as an actual tornado warning would.